[MD settings] end of page padding in content area

chrome/browser/resources/settings/settings_main/settings_main.js

Index: chrome/browser/resources/settings/settings_main/settings_main.js
diff --git a/chrome/browser/resources/settings/settings_main/settings_main.js b/chrome/browser/resources/settings/settings_main/settings_main.js
index f9afe10053f9bbe4649a97a3c3b9115cdebe440d..e8fef49682ba892340a2a252db42e1e2d214087d 100644
--- a/chrome/browser/resources/settings/settings_main/settings_main.js
+++ b/chrome/browser/resources/settings/settings_main/settings_main.js
@@ -118,6 +118,48 @@ Polymer({
         newRoute.page == 'advanced';
 
     this.style.height = isSubpage ? '100%' : '';
+
+    /* Flush the dom-if changes prior to calculating the overflow padding. */
+    Polymer.dom.flush();

[Dan Beam, 2016/07/02 00:17:31]

can't we just do:

this.async(function() {
  this.$.overscroll.style.paddingBottom = ...;
});

[dschuyler, 2016/07/02 00:23:55]

Done.

+    this.$.overscroll.style.paddingBottom =
+        (this.parentNode.scrollHeight - this.lastSettingsElementHeight_()) +
+        'px';
+  },
+
+  /**
+   * Return the height of the last item in the settings content area. Used to
+   * determine how much padding to apply to the end of the content so that the
+   * last element may align with the top of the content area.
+   * @return {number}
+   * @private
+   */
+  lastSettingsElementHeight_: function() {
+    if (!this.currentRoute || this.currentRoute.subpage.length != 0 ||
+        this.showAboutPage_) {
+      return 0;
+    }
+
+    /**
+     * @param {Element} element
+     * @return {number}
+     */
+    function calcHeight(element) {
+      var style = getComputedStyle(element);
+      return element.offsetHeight + parseFloat(style.marginTop) +
+          parseFloat(style.marginBottom);
+    }
+
+    if (this.showAdvancedPage_) {
+      var sections = this.$$('settings-advanced-page').$$(
+          '[data-page=advanced]').querySelectorAll('settings-section');
+      return calcHeight(sections[sections.length - 1]);
+    }
+
+    var toggleContainer = this.$$('#toggleContainer');
+    if (toggleContainer)
+      return calcHeight(toggleContainer);
+
+    return 0;
   },
 
   /** @private */